Transmission synchronizer



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Y TRANSMISSION SYNCHRONIZER Filed June 9, 1938 P i 39 1 j 2l; 23 j@ 3 25l 20 60- 2j Z5 /f 27 gl Q Patented Nov. 19, 1940 Vaughn Haigh. Muncie,Ind@ assignor to Borg- Warner Corporationihicago, Ill., a corporation`of `Illinois Application June 9, 19',sena| No. 212.363

15 claims. (c1. 19a-53) This invention relates to synchronizingchangespeed gear transmissions of the ty'pe employed, for example,inmotor vehicles, wherein there is provided means for effectingsynchronization of a pair or pairs of torque-transmitting memberspreparatory' to connecting said members in positive drive engagementwith each other.

The invention is particularly directed to synchronizing transmissions ofthe type whereinthe synchronizing means comprises friction clutchelements adapted to become drivingly engaged with each otherin theinitial stage of shifting movement, as a result of axial thrusttransmitted to one of such elements from the movable jaw Vclutchelement, and wherein there is incorporated so-called .blockerf mechanismfor preventing the positive drive engagement of the members prior to thetime that synchronization -is effected.

The invention is directed to the improvement 'of the meansffortransmitting axial thrust from the movableclutch element to thesynchronizing element of a` transmission of the type specified, and hasas one of its objects to provide a transmission of this type in whichthe shifting operation may be accomplished with greater ease andsmoothness than is possible in transmissions now available. Specically,the invention contemplates greatly modifying, or eliminating entirely,

the "poppet or break-away connection between the movable clutch elementand the thrusttrans mitting means, conventionally employed insynchronizing transmissions.

The invention contemplates the employment 36 of a plurality of4 axiallydisposed `thrust-transmittng bars for transmitting thrust from themovable clutch element to the synchronizer element, and provides forfrictional thrust-transmitting engagement between Ythe bars and the 40interior, of the movableclutch sleeve. Instead of making a directfrictional contact of the movable clutch element against the barsthemselves, however, which would restrict the frictional engagement tothe limited area of the bars, the inventionprovides a drag ring,`whichis adapted to Afr ictionally engage the interior of the movable clutchsleeve around its entire circumference, and which has a.Q positivethrust-transmitting connection with the bars. A

Another object of the invention is to provide a synchronizingtransmission which, -in addition to the foregoing characteristics, isrelatively simple and inexpensive in construction. n

Another object of the invention is to provide.

of structurally independent thrust bars are tied together in such amanner that they are enforced to maintain positions in which their endsregister in a common plane at right angles to the major axis of thetransmission, so that pressure will be Kdistributed equally around thecircumference of the synchronizer-ring during the synchronizeroperation.

Other objects, the advantages and uses of the invention will`becomeapparent after reading the following specification and claims, and afterconsideration of the drawing forming a part of th specification,wherein: i

Fig. 1 is an axial sectional view of a. portion of a motor vehicletransmission embodying the inu vention;

Fig. 2 is a transverse sectional view of the same, taken as indicated bythe line 2-2 on Fig. 1;

Fig.:3 is a transverse sectional View of the same, taken as indicated bythe line 3--3 on Fig. 1, the parts being shownin blocking position;

Fig. 4 is a plan view of coacting portions of a synchronizer ring and athrust bar of the invention; and

Fig. 5 is a fragmentary axial vsectional view of 25 a slightly modifiedform of the invention.

As illustrative of one form in which the invention may be embodied, Ihave shown in Fig. 1 a portion of a synchronizing transmission of thegeneral type disclosed in the application of Samso uel O. White, SerialNo. 168,317, filed October 11, 1937. Such a transmission may include atorquetransmitting member I0, forming the rear end of the drive shaft ofthe transmission, and torquef transmitting members, including the drivenshaft n, piioted, as at Iz, 1n the member lo, and the 35 hub member I3splined, as at I4, on the ,driven shaft II, and secured against axialmovement by retaining rings I5 and I6. Positive drive connection may beestablished between the torquetransmitting members I0 and II, or betweena reduction geared torque-transmitting member I1 and the member Il, byan axially movable `1aw clutch element `lmadapted to The shifted by ashifting fork I9 into positive clutching engagement with clutch teeth 20formed on the torque- 45 transmitting member IIJ, or clutch teeth 2|formed on the torque-transmitting member I1. To this end, the movableclutch element I8 is formed with internal clutch teeth 22,-in lslidingsplined 'engagement with teeth 23 forming the' 5o periphery of the hubmember liL'andadapted to engage the clutch teeth 20 or 2| when\movedaxially.

The torque-transmitting member I1 comprises part of a reduction geartrain driven from a pin- 85 ing arrangement.

ion 24 on the drive shaft IIJ, through the medium `oi a conventionalcountershaft, such as is shown in the White application above referredto. Upon being moved into clutching engagement with the 5 clutch teeth20, the clutch member I8 will receive rotation from the drive shaft Iand transmit it directly through the hub I3- to the driven shaft II.Upon being moved -in the opposite direction into clutching engagementwith the teeth 2| the l0 clutch member I8 willreceive rotation from thetorque-transmitting member' I1 through the countershaft just referredto, and will transmit it through the hub member I3 to the driven shaft II.

In order to synchronize a torque-transmitting l5 member Ill or I1 withthe hub I 3,` preparatory to establishing such clutching engagement, Iprovide apair of synchronizer-rings 25 each including a. substantiallycylindrical ,collar portion 26 rotatably floating in an annular groove21 extending axially into the hub member I3, and a radially outwardly.extending ange 28 formed with blocker teeth 29 between which the teeth22 of the movable clutch element must pass before the clutchingengagement may be had with the clutch teeth 20 or 2|. The opposed-endsof the teeth 22 and 29 may be chamfered, as shown at 30 and 3Irespectively. The synchronizer rings 25 are provided with internalconical clutch faces 32 adapted to engage external conical clutch faces'33 and 34 respectively, formed on the torquetransmitting members I0 andI1. The rings 25 are adapted to be located and supported by the clutchfaces 33 and 34; Intervening oil films prevent destructive wear as aresult of such support- In order to effectinitial clutching engagementbetween a friction clutch face 33 or 34 and acooperatingfrictionface 32on a ring 25, a ring 25 is moved axially by axial thrust transmitted toit from the movable clutch element through the medium ofaxially'disposed thrust bars 35. The thrust bars 35 may be of anycross-sectional shape, although it is preferred to make them rectangularasshown.' They may be very simply and inexpensively made by cuttingsections from a rec- 55 portions received in the notches 31, is a dragring 38 of spring material. As .a result of itsengagement in the notches31, the ring 38 is axially fixed with respect to the bars 35, andadapted topositively transmit axial thrust thereto. The outer side ofthe ring 38 frictionally engages the internal teeth 22 of the movablevclutch element I8, being c'oniined thereby under compression, vandtherefore urged by 'its own expanding pressure into such frictionalengagement. Since it engages all of the teeth. 22, the ring 38 isadapted to receive, as a result of such frictional engagement,considerably more axial thrust than could'be transmitted throughfriction directly to the bars 35. Y The engagement cf t-hev ring 38against the teeth 22 may be purely a frictional one, as inthe form shown'in Fig. 5. However, I prefer to provide a very shallow annular groove39 in the teeth 22,'

adapted to receive the ring 38 when the movable clutch sleeve i8 is inneutral position, as shown `ing mechanism against' the synchronizer ringwill in Fig. 1. This gives a'slight poppet action without developing theresistance to break-away that is characteristic of the conventionalpoppet construction. This construction also is considerably lessexpensive than the conventional poppet 5 construction. I nd that inoperation, the action is exceedingly smooth and easy.

The ends of the thrust bars are received in axially opening notches 40in the synchronizer rings 25, as shown in Fig. 4. The notches 48 are 10circumferentially elongated suiciently so tha-t the synchronizer ringsmay have a limited amount of .circumferential movement relative to thehub I 3 before being stopped by contactl with the thrust bars 35. Whenat one limit of suchcircumferen- 15 tial movement, a synchronizer ringwill be in a blockingposition wherein its blocker teeth 29 will obstructaxial advance of the movable clutch eiement I8 by engaging the teeth 22thereof.

It is contemplated that the friction faces 32 20 of the synchronizerrings 25 and the friction faces 33 and 34 respectively, may be soclosely .associated when the movable clutch element is in neutralposition, that a film. of oil may exist between these faces and develop,under relative rotation thereof, a-slight oil drag tending constantly tobias the synchronizer rings toward the limits.of their lost motionconnections. Should a synchronizer ring fail to be biased in blockingposition at the beginning of a shifting operation, the initial stage ofshifting movement will cause thrust to be transmitted from the sleeve I8to the ring 38,`from the ring 38' to the bars/35, and from the bars 35to the synchronizer ring 25, so asto 35 cause the latter to frictionallyengage its cooperating friction clutch element with suiicient intensityto cause the ring to become biased. Additional'axial thrust exertedthrough the shiftincrease the frictional engagement to such` an "oextent that the engaging faces will move toward synchronization'. Should.an impatient operator exert an undue amount of pressureagainst theshift lever, sufficient' to cause the movable clutch element to slipwith relation to the thrust bars 35,

priorv to synchronization, the synchronizer voperathe movable clutchelement I8 are in register with the spaces between the blocker teeth 29,`whereupon the teeth 22, which have already commenced 50 to move intosuch spaces,owing to the chamfered faces 30 and 3| of therespective'sets of teeth, will, under the continuous urging pressure ofthe shifting member I9, slide between the teeth 29 and into engagementwith the now synchronized g5 clutch teeth 28 or 2 I. In this stage ofmovement, the resistance, toY advance of the movable clutch element hasbeen reduced to the relatively small resistance occasioned by theengagement between the ring 38 and the teeth 22 of the movable clutch 70sleeve I8.

The invention provides an arrangement wherein a plurality ofstructurally independent thrust bars are tied together'againstindependent lon'- gitudnal movement, and thereby maintained at 75frictional engagement between the sleeve and the bars, or unequalresistance to their movement, is eliminated.

I claim: 1. In a synchronizing transmission, a pair of axially alignedtorque-transmitting members, synchronizer and movable jaw clutchelements drivingly associated with one of said members and movableaxially into frictional driving and positive clutching engagement,respectively, with friction and jaw clutch elements carried by the othermember, so as to establish rst a synchronizing and then a positive driveconnection between said members, and means for transmitting axial thrustfrom said movable clutch element to said synchronizer element foreiecting said frictional driving engagement, comprising a plurality otaxially disposed thrust bars radially interposed between said movableclutch element and said one torque-transmitting member, said bars havingtheir ends disposed in abutting, thrust-transmitting relationship tosaid synchronizer element and arranged to receive axial thrust from saidmovable clutch element, and means constantly engaged in transversenotches in said bars defined between surfaces which are perpendicular tothe axis ofthe torque transmitting members, and tying said bars togetherso as to constrain them to move collectively while maintaining positionswith their ends registering in .a common plane at right angles to theaxisofmovement,

A2. In 'a synchronizingtransmission, a pair ofl vaxially alignedtorque-transmitting members,

synchronizer and movable jaw clutch elements drivingly associated withone of said members and r movable axially into frictional driving andpositive clutching engagement, respectively, with friction and jawclutch elements carried by' the other member, so as to establish rst asynchronizing and then a positive drivel connection between saidmembers, and means for transmitting axial thrust from said movableclutch element to said synchronizer element for effecting saidfrictional driving engagement, comprising a plurality of axiallydisposed thrust bars radially interposed between said movable clutchelement and said one torque-transmitting member, said bars having theirends disposed in abutting,

thrust-transmitting relationship to said synchro nizer element, andmeans tying said bars together so as to constrain them to movecollectively with their ends at all times in register in a common planeat right angles to the axis of movement, said means being in engagementwith the interior. of said movable clutch element so as to receivethrust therefrom.

3. In a synchronizing transmission, a pair of axially alignedtorque-transmitting members, synchronizer and movablev jaw clutchelements drivingly associated with one of said members and movableaxially into frictional driving'and positive clutching engagement,respectively, with friction and jaw clutch elements carried by the othermember, soas to` establish first a synchronizing and thn a positivedrive connectionbetween said members, and means for transmitting axialthrust from said' movable clutch element to said synchronizer elementfor eiecting said Irictional driving engagemenmcomprising a plurality ofaxially disposed thrust b ars radially interposed between said movableclutch element and'said one torque-transmitting member, said bars havingtheir ends disposed in abutting, thrust-transmitting relationship tosaid synchronizer element, and a drag ring radially inter-4 posedbetween said thrust bars and said movable clutch element, said ringbeing ln axially yieldable thrust-transmitting engagement with saidmovable clutch element and in axially xed thrust-transmitting engagementwith said thrust' 4. In a synchronizing transmission, a pair ortorque-transmitting members mounted in axial alignment, an annularvmovable jaw clutch elemgit surrounding and carried by one of saidmembers and adapted to be moved into engagement with a jaw clutchelement carried by the other'member, thus to establish a positive driveconnection between said members, ay synchronizer element associated withsaid one torquetransmitting member and adapted under axial pressure toestablish frictional synchronizing engagement with said othertorque-transmitting member to establish a friction drive between saidmembers, and means for transmitting axial thrust from said movableclutch element to said synchronizer element for effecting saidfrictional driving-engagement, comprising a plurality of axiallydisposed thrust bars radially interposed between said movable clutchelement andA said one torque-transmitting member, and having their endsdisposed in abutting, thrust-transmitting relationship to saidsynchronizer element', and a drag ring radially interposed between saidthrust bars and said movable clutch element, said ring being in axiallyyieldable thrust-transmitting engagement ywith said movable clutchelement' and in axially fixed thrust-transmitting engagement with saidthrust bars.

5. A synchronizing transmission as defined in claim 4, wherein theengagement between said ring and said movable clutch element is a purelyfrictional one.

6. A synchronizing transmission as dened in claim 4, wherein saidmovable clutch' element is provided with a shallow annular groove inwhich said ring engages when the movable clutch element is inneutral-position.

7. A synchronizing transmission, as dened in claim 4, wherein the saidengagement between said ring and bars is furnished by transverse groovesin the outer regions of the bars, receivingcircumferentially spacedportions of said ring.

8. A synchronizing transmission, as defined in claim 4, wherein the saidengagement between said ring and bars is furnished by transverse notchesin the radially outer regions of said bars', receiving circumierentiallyspaced portions of said ring, and wherein' said movable clutch elementis provided in its interiorv with a shallow annular groove in which saidring engages when the movable clutch element is in neutral position.

9. In a synchronizing transmission, a pairAof axially alignedtorque-transmitting members, one of which includes a hub, a movable jawclutch sleeve having internal teeth in axially shiftable splinedengagement with teeth on said hub, said sleeve being adapted to be movedaxially into engagement with a jaw clutch element carriedby the othertorque-transmitting member, thus to establish a positivedriveconnection, a

synchronizer element adapted under axial pressure to establishfrictional synchronizing engagement with said other member, having alost motion driving connection with said hub, and

lincluding blocking teeth adapted, inone of its element, and a drag ringradially interposed between said thrust bars and said movable clutch'sleeve,'in expanding, yielding frictional thrust` transmittingengagement with said internal teeth of the sleeve, said bars having intheir outer regions, transverse notches receiving portions of said dragring whereby the latter is in axially fixed thrust-transmitting relationto s'aid bars.

10. In a synchronizing transmission, axially aligned driving and drivenshafts, opposed jaw clutch elements drivingly associated with therespective shafts, a hub carried by one of the shafts and disposedbetween said jaw clutch elements, a movable jaw clutch sleeve havinginternal clutch teeth splined upon the periphery of said hub and axiallymovable into positive clutching 'engagement with either of said jawclutch elements, opposed synchronizer cones drivingly associated withopposite sides of said hub and adapted under axial pressure to establishfrictional synchronizing engagement with coacting friction clutchmembers drivingly associated with the respective law clutch elements,and means for transmitting axial thrust from said sleeve to either ofsaid synchronizer cones, comprising a plurality of thrust bars radiallyinterposed between said sleeve and said hub, and havv ing their endsdisposed in abutting, thrust-transmitting relation to the respectivesynchronizer cones, and a drag ring radially interposed between saidthrust bars and said movable clutch element, said ring being in axiallyyieldable thrust-transmitting engagement with the internal teeth of saidsleeve, and in axially fixed thrust-transmitting engagement with saidthrust bars. Y

11. In a synchronizing transmission, a pair of axially aligned torquetransmitting members, synchronizer and movable Jaw clutch elementsdrivingly associated with one. o! said members and movable axially intofrictional driving and positive clutching engagement, respectively, withfriction and jaw clutch elements drivingly associated with the othermember, thereby to establish first a frictional and then apositive-driving connection between said members, and means forytransmitting axial thrust from said movable Yclutch element to saidsynchronizer element for tingrelationship to said synchronizer element,I

and means tying said bars together against independent axial movement,said means being in engagement with the interior of said movable clutchelement so as to receive thrust therefrom.

12. In a synchronizing transmission, a pair of axially aligned torquetransmitting members,

synchronizer i and movable jaw clutch elements drivingly associated withone of said members and movable axiallyinto frictional driving andpositive clutching engagement, respectively, with friction and jawclutch elements carried by the other member, so as to establish rst africtional and then a positive driving connectionbetween said members,and means for transmitting axial thrust from saidmovable clutch elementto said synchronizer element for effecting said vfrictional drivingengagement, comprising a plurality of axially disposed thrust barsradially interposed between said movable clutch element and said onetorque transmitting member, and axially movable relative to-both, saidbars being in positive thrust transmitting relationship to saidsynchronizer element, and a drag ring radially interposed between saidbars and said movable axially movable into positive clutching engagementwith either of said jaw clutch elements, opposed synchronizer conesdrivingly associated with opposite sides of said` hub and axiallymovable into frictional driving engagement with coactlng friction clutchelements drivingly asso'- ciated with the respective jaw clutchelements.

y and means for transmitting axial thrust from' said sleeve to either ofsaid synchronizer cones,l

comprising a plurality of thrust bars radially interposed between saidsleeve and said hub and arranged in positive thrust transmitting rela-Vtionship to the respective synchronizer cones,

and a drag ring radially interposed between said thrust bars and saidmovable clutch elements, said ring being in axially yieldable thrusttransmitting engagement with the internal ,teeth of -said vsleeve and inaxially fixed thrust transmitting 'engagementwith said thrust'bars.

14. In a synchronizing transmission, a pair of axiallyaligned torquetransmitting members, synchronizer and movable jaw clutch elementsdrivingly associated with one of said members and movable axially in tofrictional driving and positive clutching engagement, respectively, withfriction and jaw clutch elements carried by the other member, so as toestablish first a synchronizing and then a positive drive connectionbetween said members. and means for transmitting axial thrust from saidmovable clutch element to said synchronizer element for effecting saidfrictional driving engagement, comprising a plurality of axiallydisposed thrust bars radially interposed between said movable clutchelement and said one torque transmitting member, said bars beingarranged in positive thrust transmitting-relationship to saidsynchronizer element, and a drag ring radially interposed between saidthrust -bars and said vmovable clutch element, said ring` being inaxially yieldable thrust transmitting engagement with said movableclutch element and engaged in transverse notches in said thrust bars.

15. I n a synchronizing transmission, a pair ofaxially aligned torquetransmitting members, one of which includes a hub portion, a movable jawclutch 'sleeve having internal teeth in axialiy shiftable splined ntwith teeth on said hub, vsaid sleeve being adapted to be m'oved axiallyinto engagement with a jaw clutch element carried by the other torquetransmitting member, thus to establish a positive drive connectionbetween said members, a synchronize: element axially recessed into anddrivinsly connected to said hub portion, said synchronizer eiement beingaxially shiftable into frictionai driving engagement with a coactingfriction clutch element drivingly associated with the other torquetransmitting member, and means for transmitting axial thrust from saidmovable jaw clutch sleeve to said synchroniser element for effecting`said i'rictional driving engagement.. comprising a plurality of axiallydisposed thrust bars radially interposed between said sleeve and saidhub, and arranged in positive thrust transmitting relationship to. saidsynchronizing element .and in yielding thrust receiving relationship tosaid sleeve. and means tying said bars tolrher against independent axialmovement.

VAUGHN HAIGH.

